This invention relates to adjustable passenger seating arrangement for vehicles, particularly aircraft.
Airlines require high utilization of their aircraft and it is uneconomic for an airliner to remain grounded for many hours in any twenty four hour period. However, the demand for seats on daytime flights is substantially greater than that for night flights. On the other hand, it is desirable to provide increased longitudinal spacing between seats on night flights so as to allow passengers to adopt a more comfortable sleeping position.
In an aircraft passenger cabin, it is commonplace for two or three passenger seats to be mounted on a common seat structure aligned and engaging longitudinally extending seat rails mounted on the floor or an underlying floor support structure. The seat-to-rail attachments generally comprise rail-engaging feet for resisting pitching forces, a deployable plunger for resisting fore and aft loads and an anti-rattle device to minimize or prevent chatter between the feet and the rail. Conventional feet comprise a shank portion engaging the seat structure terminating in a frusto-conical base portion engaging the rail. Each rail, of well known form, includes a passageway extending longitudinally therethrough whose lateral cross-section conforms substantially to the frusto-conical base portion and a series of equally spaced circular holes of diameter similarly conforming to that of the base portion extends between the passageway and the rail upper surface each pair of holes interconnected along a longitudinal centre line datum by a parallel slot of width at least equivalent to the foot shank diameter. This arrangement consequently provides a combination of circular apertures into which the feet are inserted and lips under which the frusto-conical base engages when the seat is moved forwards or rearwards one half pitch into locking engagement with the rail. The number of feet, associated with a particular seat assembly, depends on the loading characteristics but their fore and aft spacing will always conform with the rail configuration. Similarly, the fore and aft restraint usually a deployable plunger, is of diameter conforming to the circular aperture in the rail with which it is adjacently positioned in a fore and aft sense to engage when the feet are moved into locking engagement with the rail.